1. Field of the Invention
The present invention relates to a video fingerprinting apparatus and method. More particularly, the present invention relates to an apparatus and method of video fingerprinting in a frequency domain, protection from recompression of a video.
2. Description of the Related Art
Multimedia data may be easily copied and transformed via a network due to the generalization of digital media and the development of various multimedia data transmission devices, storage devices, and authoring tools. Since multimedia data may be easily copied, new services are provided and pirate copies of copyrighted contents of digital media can be generated.
Fingerprinting protects the copyright of the digital media, in which a signature of an author or fingerprint for verifying the author is inserted in the digital media to be extracted to solve any problems with respect to the copyright of the digital media.
A conventional method of video fingerprinting in a space domain may quickly insert a fingerprint by using a color property before image compression. However, the conventional method additionally requires a recompression process after the inserting of the fingerprint and is vulnerable to a frame conversion attack.
In a conventional method of video fingerprinting in a compressed domain by managing a bit stream in the compressed domain, since a fingerprint is directly inserted into or extracted from an encoded discrete cosine transform (DCT) coefficient, the conventional method is very vulnerable to a recompression attack with respect to the video.
The Cox and Langelarr methods are representative examples of the conventional method of fingerprinting in a compressed domain. According to the Cox method, the fingerprint is seriously compromised when a bit rate and a frame structure are changed while recompressing a moving picture since an inserted fingerprint only affects a frequency property in the compressed domain. The shaping of the fingerprint requires an additional operation.
Though a very quick operation is possible, the Langelaar method has a structure very vulnerable to moving picture recompression.
Accordingly, there is a need for an improved system and method of video fingerprinting in a frequency domain, which is protected from video recompression.